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Flea-associated illnesses in cats

Ctenocephalides felis commonly infests cats in many areas of the United States and is associated with a variety of clinical syndromes.1 In small kittens, a heavy infestation can cause anemia, particularly if they are concurrently infected with the common parasite Ancylostoma tubaeforme or Ancylostoma braziliense.2 Repeated flea exposure can result in flea-bite hypersensitivity, one of the most common flea-associated syndromes.3, 4 Because C. felis ingests feline blood, a number of blood-borne infectious agents, including Bartonella quintana, Bartonella koehlerae, Bartonella henselae, Bartonella clarridgeiae, Rickettsia felis, Wolbachia pipientis, 'Candidatus Mycoplasma haemominutum,' Mycoplasma haemofelis, and feline leukemia virus (FeLV), have been grown or amplified by polymerase chain reaction (PCR) assays from C. felis or its feces.5-18Ctenocephalides felis is a vector for some of these infectious agents. And because some of these agents are human pathogens, the American Association of Feline Practitioners (AAFP) recommends continual flea control to potentially reduce the risk of exposure.19 This article will provide a brief update on Bartonella and Mycoplasma species infections in cats.

Bartonella species infectionsBartonella henselae is the most common cause of cat scratch disease as well as bacillary angiomatosis and bacillary peliosis, which are common disorders in people with acquired immunodeficiency syndrome (AIDS).19-21 People with cat scratch disease develop a variety of clinical signs, such as lymphadenopathy, fever, malaise, weight loss, myalgia, headache, conjunctivitis, skin eruptions, and arthralgia. Bacillary angiomatosis is a diffuse disease resulting in vascular cutaneous eruptions. Bacillary peliosis is a diffuse systemic vasculitis of the parenchymal organs. Most cases of cat scratch disease are self-limiting, but some cases may take several months to resolve completely. Cats can also be infected with B. clarridgeiae, an organism that has been associated with cat scratch disease.22

Based on seroprevalence studies in cats, exposure to Bartonella species is very common and varies by region in the United States.23 The organism is transmitted by fleas, so prevalence is highest in cats from states where fleas are common.6, 9Bartonella henselae survives in flea feces for days after it's passed by infected C. felis.8, 10 In a recent study, we collected fleas from cats and attempted to amplify Bartonella species DNA from flea digestsas well as cat blood (Lappin MR, Unpublished data, 2005). The prevalence rates for B. henselae infection in cats and their fleas were 34.8% and 22.8%, respectively. The prevalence rates for B. clarridgeiae infection in cats and their fleas were 20.7% and 19.6%, respectively.

Clinical signs
Most cats with positive Bartonella antibody titers, Bartonella species cultured from the blood, or organismal DNA amplified from the blood by PCR assay are clinically normal.

However, Bartonella species infection in cats has also been associated directly and indirectly with clinical manifestations such as fever, lethargy, lymphadenopathy, uveitis, gingivitis, and neurologic diseases. How often cats become ill from Bartonella species infections is unknown and more information is needed.